Interpretive Summary: The corn fungus Fusarium moniliforme produces fusaric acid which behaves like a weak animal toxin, but when it is combined with other mold toxins, it exaggerates the effects of the other toxin. Scientists consider that this may be the important role for fusaric acid. Further, RRC scientists established that fusaric acid is found in most corn and corn based feed. The objective of this present work was to determine how many isolates of the corn mold, as well as other species of the mold (Fusarium), produce fusaric acid. The results indicate that all isolates of the corn fungus and other Fusarium-type molds produce this toxin suggesting that this compound is probably more prevalent in the environment than initially considered. For example, these fungi can infect well over 5,000 species of plants and several hundred of these are agriculturally important. The substance may be used as a presumptive test for Fusarium contamination. These results indicate that analyses and toxicity studies should also include this toxin along with other suspect toxins under field conditions.

Technical Abstract:
Fusaric acid is a mycotoxin with low to moderate toxicity that is of concern since it might be synergistic with other co-occurring mycotoxins. Fusaric acid is widespread on corn and corn-based food and feeds, and is always found in grain where Fusarium spp. are also isolated. We surveyed 78 strains from Fusarium moniliforme, F. crookwellense, F. subglutinans, F. sambucinum, F. napiforme, F. heterosporum, F. oxysporum, F. solani and F. proliferatum for their ability to produce fusaric acid. Strains in Fusarium section Liseola also were assigned to mating population of the Biggerella fujikuroi species complex. The fungi could be divided into three classes: low (<100 ug/g), moderate (100-500 ug/g) or high (>500 ug/g), based on the amounts of this mycotoxin produced in culture on autoclaved corn. Studies of mating populations C from rice consistently produced moderate to high concentrations of fusaric acid. Two isolates, one each from mating populations C and D, produced fusaric acid in excess of 1000 ug/g of corn. No isolates of these fusaria were negative for the production of fusaric acid.